1982 Volume 102 Issue 10 Pages 911-922
Four germacranolide lactones 1, 1a, 2 and 2a were isolated from the underground parts of Ainsliaea acerifolia var. subapoda (Compositae). Their structures were determined by chemical and spectral studies. The structures should be represented by 1 : [1 (10) Z, 4E]-6βH, 7αH-germacra-1 (10), 4, 11 (13)-trien-12, 6-olide-14-O-β-D-glucopyranoside : 1a : [1 (10) Z, 4E]-6βH, 7αH-germacra-1 (10), 4, 11 (13)-trien-12, 6-olide-14-oic acid ; 2 : [4Z, 9Z]-6βH, 7αH-germacra-4, 9, 11 (13)-trien-12, 6-olide-14-O-β-D-glucopyranoside and 2a : [4Z, 9Z]-6βH, 7αH-germacra-4, 9, 11 (13)-trien-12, 6-olide-14-oic acid, respectively. Conformations of 1a and 2a were determined by nuclear overhauser effect studies. The spectral data for 1 (bitter principle), 1-tetraacetate (1c) and 1a were in agreement with the data for Taraxinsaure-1'-O-β-D-glucopyranoside (3), 3-tetraacetate (3b) and 3-hydrolyzate (3a), respectively. The new natural compounds 1a, 2 and 2a were named Taraxinsaure, ainslioside and ainsliolide, respectively.
